This invention relates to an apparatus and method for ensuring proper registration of a mailpiece in a postage meter and more particularly to a method and apparatus for initiating printing and properly registering a mailpiece in a stand alone postage meter to ensure accurate orientation of a printed postal indicia on the mailpiece.
In a typical stand alone postage meter, a mailpiece (envelope, flat, etc.) is fed into the meter by hand rather than by use of an automatic feeder. When an edge of the mailpiece is detected by a trip sensor, the postage meter initiates printing under the assumption that tripping of the trip sensor by the mailpiece indicates that the mailpiece is properly registered relative to the printing mechanism so that a correctly oriented indicia image will be printed on the mailpiece. However, in conventional trip sensor structures for stand alone postage meters, the trip sensor is typically configured to detect the presence of a single edge of the mailpiece. Thus, if the mailpiece is presented in a skewed manner such that the trip sensor can still be tripped, the printed indicia image will be misaligned or perhaps, even worse, only part of the indicia image will be printed on the mailpiece. Moreover, if the mailpiece being presented to the postage meter is, for example, not very stiff, it may be bent as it is forced against a back registration wall of the postage meter. If the trip sensor is disposed in the back registration wall, it will be tripped to initiate printing. However, due to the bending of the envelope, its leading edge will be bowed and not properly registered against a leading edge registration wall. It is therefore possible that the top mailpiece surface upon which the indicia is to be printed will not be presented to the printing device in the proper orientation which is required to produce a properly aligned indicia image without smearing of the ink.
The problem discussed above concerning the relative positioning of the top of the mailpiece with respect to the printing mechanism becomes even more important in the case of an ink jet printer where maintaining, within tight tolerances, the distance between the printer nozzles and the top surface of the mailpiece is often critical to ensure that a good image is produced. Thus, as the postage meter industry moves toward using ink jet printers in postage meters, the need for ensuring that printing is only initiated when the mailpiece is properly registered becomes even more critical than in the past.